Answer: lava

AnswerCrossword Clue
LAVAPumice source
LAVAMaterial for a volcanologist
LAVAStromboli stuffing?
LAVAIgneous rock, originally
LAVARock that runs
LAVARock made liquid
LAVARock that's hot
LAVAKilauea flow
LAVAMagma on the surface
LAVASpatter cone's output
LAVAHot rock
LAVARed-hot rock
LAVADestructive flow
LAVARed flower?
LAVARock found in rivers
LAVABasalt, once
LAVAIt forms obsidian
LAVAHawaiian flower?
LAVARed-hot outpouring
LAVAEtna flow
lavamolten rock from a volcano
LAVAHot issuance?
LAVAHot rock?
LAVAHot stuff
LAVAPumice, essentially
LAVAVolcano output
LAVAFluid rock
LAVAHawaiian heat
LAVAVolcanic flow
LAVABody shop soap
LAVAEtna output
LAVAFuji flow
LAVAVolcanic flower
LAVAVolcano's output
LAVANot-so-hard rock?
LAVANash's priest
LAVAHot issue?
LAVAMolten rock
LAVAObsidian, once
LAVAPinatubo flow